Yuito's memory of his childhood savior returns. While off duty, Yuito and Nagi run into Naomi and Kasane. Something is afoot in Seiran, but is it related to Karen's agenda? The Seto and Kyoka platoons train, and then scramble to intercept the Others.

Something goes horribly wrong with Naomi, leaving her comrades dazed and confused. It's clear there is more to it when they're told to keep quiet. Kasane divulges a shocking secret to Yuito, and the Seto and Kyoka platoons face an unexpected enemy.

Karen's machinations lead to a battle between comrades until a new threat arrives, claiming all around it. Yuito and company lick their wounds as they learn about Karen's motives. Others swarm into Suoh, and Kasane and company awake in a strange place.

As Karen's revolt gathers steam, Yuito and forces loyal to New Himuka are hard-pressed. Fubuki takes command of a band of loyalists and orders Yuito to check that his father is safe. Karen publically reveals a motive, and Yuito has a shocking encounter.

Kasane and company wake to a shocking reality and strange encounters. Kasane learns about the void in the sky and a way to stop it. Yuito and Kasane clash after she finds out what is behind Karen's revolt. Kasane heads to Seiran with other OSF members.

Friends become enemies as the OSF splits in two. Yuito receives a promotion, but why can't he remember? Karen creates a new Seiran OSF platoon and tells Kasane they have Naomi in their care. The hunt for Nagi is on as Yuito gains fresh intel.

The hunt for Nagi continues. Yuito's platoon is ambushed but makes a narrow escape. Fubuki and Luka reveal the hospital's secrets and the dark truths behind them. Kasane's platoon searches for Naomi. Karen offers to help with Naomi's condition.

Fubuki reveals his mindset to Yuito. After approaching Kaito, Fubuki's plan takes shape. Yuito's ailment worsens, and he tries the drug he was prescribed. His platoon discovers a secret manufacturing plant and has a run-in with Kasane's platoon.

Fubuki puts his plan into action. Yuito and his platoon set out to recover Nagi's memory data. Kasane's platoon learns more about the Kunad Gate and her encounter with future Yuito. Yuito learns a shocking truth from his past. Togetsu comes into play.